Last week, I got to beta-test a new service called tuber. Tuber is the Uber of food delivery services, with a focus (okay, an obsession) on certain kinds of root vegetables.

Just as some people keep Sidecar, Lyft and Uber on their phones, so they can compare who's got the best price or service in any given moment, Tuber is working to stake out a particular niche. They'll deliver a potato, yam or cassava, usually within twenty minutes of being requested.

In my case, I got three organic Japanese sweet potatoes, delivered to my house in time to roast for dinner. They were perfect specimens, and the price was right. (In case you're interested, the recipe: 450 degree oven for an hour. Done.)

Think about how they can magnify their advantages. Unlike more general food delivery sites, they can dig deep into the entire range of tubers. They can outfit their vehicles and focus their staffing with an eye on delivering exactly what this particular consumer seeks out. If we are indeed all weird, then tuber can get to the root of what we're after.

The interesting battle happens when these specialists start to overlap. Carrots, for example, are a taproot, not technically a tuber, and yet the company appears willing to expand into this area, risking their focus. Spread too thin, there will be pressure on management to expand into green vegetables and even fruits.

On the other hand, they are now saying that legumes (like peanuts) will be handled by their sister company, guber.